1. Field of the Invention
The present invention relates to a ball screw device, and more particularly to a ball screw device including a securing or mounting structure for suitably and smoothly attaching or anchoring or securing or retaining a ball return pipe to the ball screw device and for suitably guiding the ball bearing members to smoothly move through the endless ball guiding passages of the ball screw device and the ball return pipe.
2. Description of the Prior Art
Typical ball screw devices comprise a nut threaded onto an elongated bolt or screw and rotatable and movable or adjustable along the screw, one or more endless ball guiding passages formed in the ball screw device for slidably receiving ball bearing members, and one or more ball return pipes attached onto the ball screw device for guiding the ball bearing members to smoothly and suitably move through the endless ball guiding passages of the ball screw device.
For example, U.S. Pat. No. 6,023,991 to Yabe et al. discloses one of the typical ball screw return systems comprising a ball return pipe engaged onto the ball screw nut with a tube holder member and fasteners for guiding the ball bearing members to smoothly move through the endless ball guiding passage of the ball screw device, and the ball return pipe include two tubular tongues formed in the ends for engaging into the nut.
However, the ball return pipe may not be precisely secured to the nut, and the tubular tongues of the ball return pipe may not be precisely directed toward the endless ball guiding passage of the ball screw device, or the ball return pipe may not be precisely meshed with the nut such that one or more projections or protrusions may be extended into the endless ball guiding passage of the ball screw device and may interfere the movement of the ball bearing members through the endless ball guiding passage of the ball screw device.
U.S. Pat. No. 6,089,117 to Ebina et al. discloses another typical ball screw and nut assembly comprising a ball return pipe engaged or attached or secured onto a nut with a standard hose clamp for guiding the ball bearing members to smoothly move through the endless ball guiding passage of the ball screw and nut assembly.
However, similarly, the ball return pipe may not be precisely secured to the nut, and the tubular tongues of the ball return pipe may not be precisely directed toward the endless ball guiding passage of the ball screw device, or the ball return pipe may not be precisely meshed with the nut such that one or more projections or protrusions may be extended into the endless ball guiding passage of the ball screw device and may interfere the movement of the ball bearing members through the endless ball guiding passage of the ball screw device.
U.S. Pat. No. 6,481,305 to Nishimura et al. discloses a further typical ball screw device also comprising one or more ball return pipes attached onto the ball screw nut and each having two bent tubular ends engaged into the ball screw nut for guiding the ball bearing members to smoothly move through the endless ball guiding passage of the ball screw device.
However, the ball return pipe may not be precisely secured to the nut, and the tubular tongues of the ball return pipe may not be precisely directed toward the endless ball guiding passage of the ball screw device, or the ball return pipe may not be precisely meshed with the nut such that one or more projections or protrusions may be extended into the endless ball guiding passage of the ball screw device and may interfere the movement of the ball bearing members through the endless ball guiding passage of the ball screw device, and may be broken by the ball bearing members when the ball bearing members are moved in a fast speed through the endless ball guiding passage of the ball screw device.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional ball return pipes for the ball screw devices.